JPS6070795A - Method of producing printed circit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a printed wiring board in which a circuit pattern is printed on a printed wiring board.

In the manufacture of printed wiring boards, when a photoresist is laminated onto a printed wiring board that has been chemically or mechanically leveled, dust is removed from the surface of the substrate. The conventional dust removal method is to use gloves or a record cleaner to remove foreign matter from the board surface, but the gloves may get caught on the copper-plated edges and fibers and debris may be left behind. There are drawbacks that arise, particularly in the case of double-sided through-hole substrates.

Therefore, in recent years, a method of vacuum suction while blowing ionized air onto the substrate has been proposed as an alternative to this dust removal method.However, although the dust removal method can sufficiently remove small foreign objects, it is difficult to remove large foreign objects. .

Therefore, as a way to solve this problem, it is possible to remove dust by attaching a pressure-sensitive adhesive tape made of natural rubber to the surface of the board and then peeling it off. When used, the adhesive strength of this tape is high, making it difficult to peel the tape from the substrate, and it may remain on the substrate, interfering with the formation of clear images. Furthermore, depending on the tape, it may contaminate the surface of a substrate, reducing the adhesion of the photoresist to the substrate surface, causing the photoresist to peel off during development, or the etching solution to seep in during etching, causing disconnections in the circuit pattern. There is.

On the other hand, when natural rubber-based adhesive tape for surface protection is used, the adhesive force of this tape is low, so there is no problem with peeling workability or residual adhesive, but there is still the problem of contamination of the substrate surface and dust removal. Not practical due to reduced effectiveness.

Therefore, the inventors studied a pressure-sensitive adhesive tape suitable for removing dust from the surface of a substrate when photoresist is laminated, and as a result, they came up with the present invention.

That is, the method of the present invention - in the production of printed wiring boards - removes dust from the surface of a printed wiring board before laminating a photoresist, when the adhesive layer is made of a) chlorinated polyolefin and/or chloride comb, b) alkyl acrylate. A line consisting of an ester or meccrylic acid alkyl ester polymer and C) terephthalic acid, ethylene glycol, and a dibasic acid or dihydric alcohol other than these, with an average molecular weight of about 30,000 or less and having a carboxyl group or a hydroxyl group at the molecular end. The adhesive layer contains at least one film-forming polymeric substance selected from saturated polyesters and an ethylenically unsaturated polymerizable compound as essential components, and the adhesive layer has a thickness of 5 to 100 μm and an adhesive strength of 50 to 1 , 5009725 mm width (30° C.) is applied to the substrate surface and then peeled off.

According to the method of the present invention, by specifying the adhesive strength of the adhesive tape for dust removal and the thickness of the adhesive layer as described above, it is possible to peel off the tape after adhering it to a substrate with good workability, and Dust removal is extremely simple and effective because no foreign matter is left behind.

Furthermore, the film-forming polymeric substance and ethylenically unsaturated polymeric compound contained as essential components in the adhesive layer of this adhesive tape are both known as components constituting photoresists. By including these ingredients, the composition of the adhesive layer is the same or similar to that of the photoresist, so it does not contaminate the substrate surface, and even if adhesive remains when the adhesive tape is peeled off, Since it is compatible with the photoresist that will be laminated in the next step, it will not become integrated with the photoresist and reduce the adhesion of the photoresist to the substrate.

As a result, according to the method of the present invention, disconnection defects in circuit patterns caused by the dust removal process are eliminated, so that the reliability during manufacturing of printed wiring boards can be greatly improved [1].

Photoresists used in the manufacture of printed wiring boards include tetrafilm resists and liquid resists, depending on the method of laminating them onto a single substrate, and there are solution development types and peel-off development types, depending on the development method. Film-forming polymeric substance - consisting of a photopolymerizable composition containing an ethylenically unsaturated polymerizable compound and a photopolymerization initiator.

In the method of the present invention, at least one of the above-mentioned components a, b, and c among film-forming polymeric substances that generally constitute a photoresist is used as a component of the adhesive layer of the adhesive tape for dust removal. and an ethylenically unsaturated polymerizable compound as essential components, making the composition the same as or similar to that of a photoresist. Furthermore, in order to adjust the adhesive strength at 30°C to 50 to 1,500 g/25 rRm, preferably 100 to 500 r/25 rRm, various additives commonly used as additives for photoresists may be added as necessary. impregnate with the agent.

In addition, the adhesive strength in this specification refers to adhesive tape cut into 25 mm widths that is attached to the copper foil surface of a cleaned copper glass epoxy laminate by rolling and pressing at 25°C.
Tensilon universal testing machine UTM manufactured by Toyo Holdwin ■
-15000B, the 180° peel adhesive strength was measured at 30°C at a bow tensioning speed of 500 mm/min,
The adhesive strength of the adhesive tape for dust removal is 50P/25+++
If the width is less than +++, the dust removal effect will be low, and if the width is less than 1,500 y
/25sTn width is not preferable because the peelability of this adhesive tape becomes low.

The chlorinated polyolefin used as the above component a is obtained by chlorinating polyolefin, and chlorinated polyethylene-chlorinated polypropylene and the like are preferable. As component a, a mixture of chlorinated polyolefin and chlorinated rubber may be used, or either one may be used alone.

The acrylic acid alkyl ester or methacrylic acid alkyl ester-based polymer used as the above-mentioned component b is a homopolymer or copolymer of an acrylic acid alkyl ester such as an alkyl group or a methyl group, an ethyl group, and a probyl group. Copolymers of these esters and vinyl yarn yarns copolymerizable with these esters are included.

These components a and b are commonly used as film-forming polymeric substances constituting photoresists.

A specific example of a commercially available product containing component C is Toyobo ■
Product name: Pylon-200, -300 manufactured by Gutsdoyer ■ Product name: Hite/L/PE-200.

PE-207', PE-222, Adhesive 46950, -46960, -46981 manufactured by DuPont ■
.

-49000, -49001, -49002, Nisperu 1510, -1311 manufactured by Hitachi Chemical Co., Ltd., and the like.

When this component C is included in the adhesive layer, especially when a film made of polyethylene terephthalate is used as a support for the adhesive tape, this film will adhere very well to the adhesive layer, so during dust removal. It is preferable that the adhesive tape does not leave adhesive residue on the substrate surface.

As the ethylenically unsaturated polymerizable compound, a wide variety of known compounds having one or more ethylenically unsaturated bonds can be used. Examples of those having one ethylenically unsaturated bond include acrylic acid or acrylic esters, methacrylic acid or methacrylic esters, acrylamides, methacrylamides, allyl compounds,
Examples include vinyl ethers, vinyl esters, N-vinyl compounds, and styrene-crotonic acid esters.

Specific examples of hair acrylates include propyl acrylate, butyl acrylate, amyl acrylate, ethylhexyl acrylate-octyl acrylate, and examples of acrylic acid alkyl esters include methyl methacrylate, ethyl methacrylate, Examples include alkyl methacrylates such as propyl methacrylate and isopropyl methacrylate. Examples of acrylamides include - the scale of acrylamide - N-methylacrylamide, N-ethylacrylamide, N-
Examples include N-alkylds such as butylacrylamide, N-isopropylacrylamide, N-t-butylacrylamide, and N-ethylhexylazilylamide. Methacrylamides include C, methacrylamide, N-methylmethacrylamidropylmethacrylamide, N-methylmethacrylamide, N-ethylhexylmeccrylamide, etc.
-Alkyl methacrylamide is removed. Allyl compounds include allyl esters such as allyl acetate, allyl caproate, allyl caprylate, allyl laurate, and allyl palmitate, and the vinyl ethers include hexyl vinyl ether, octyl vinyl ether,
Examples include alkyl vinyl ethers such as decyl vinyl ether and ethylhexyl vinyl ether.

In addition, vinyl esters include vinyl butyrate,
vinyl isobutyrate, vinyl trimethyl acetate,
Vinyl diethyl acetate, vinyl valerate-vinyl caproate, etc., and examples of styrenes include styrene-based methylstyrene, chloromethylated styrene, alkoxystyrene, halogenated styrene, and benzoic styrene. Furthermore, examples of crotonate esters include methyl crotonate-ethyl crotonate, butyl crotonate, hexyl crotonate, isopropyl crotonate, and the like.

A compound having two or more ethylenically unsaturated bonds is more preferably used than a compound having one ethylenically unsaturated bond. Those belonging to this category include esters of monopolyhydric alcohols and acrylic acid or methacrylic acid, and di(meth)acrylates or poly(meth)acrylates are used. The polyhydric alcohols include polyethylene glycol, polypropylene glycol, polybutylene oxide, ((j-hydroxyethoxy)benzene, glycerin, diglycerin, neopentyl glycol, trimethylolpropane,
trimethylolpropane, pentatane, sorbitol,
1,4-butanediol, 124-butanetrionopene 2-butenoto-4-diol, 2-methyl-2-ethyl-propanediol, 2-butene-14-dio-root 3-propanediol-triethanolamine, Examples include decalin diol and 3-chloro-12-propanediol. Others - Oligoester acrylate or oligoester obtained by reacting acrylic acid or methacrylic acid with the hydroxyl group of a relatively low molecular weight polyester having one or more hydroxyl groups in the molecule synthesized from polyhydric alcohol and polybasic acid. Ester methacrylates and the like can also be used. As this commercially available product, for example, AROEX M-5500 manufactured by Toagosei ■, -5700°=61
00. -6300. -8030. -8060 etc. In addition to the above, acrylic epoxy resins may also be used.

The above-mentioned ethylenically unsaturated polymerizable compounds may be used alone or in combination of two or more, but the amount used is based on 100 parts by weight of the above-mentioned film-forming polymeric substance. Usually 10 to 300 parts by weight, preferably 50 to 300 parts by weight
It is preferable to use it in a range of 200 parts by weight.

The adhesive layer of the adhesive tape for dust removal used in the method of this invention contains the above-mentioned film-forming polymeric substance and ethylenically unsaturated polymeric compound as essential components, but it is necessary to further adjust the adhesive strength. Additives such as photopolymerization initiators, thermal polymerization inhibitors, and fillers are added according to the requirements.

Examples of photopolymerization initiators include carbonyl compounds, organic sulfur compounds, peroxides, redox compounds, azo and diazo compounds, and halogen compounds-photoreducible dyes.

To give a typical example, as a carbonyl compound,
Benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether,
Examples include benzyl dimethyl ketal-hensiphenone-anthraquinone-2-methylanthraquinone, 2-(-butylanthraquinone, 910-phenanthrenequinone, diacetyl-benzyl, etc.).Organic sulfur compounds include dibutyl disulfide, dioctyl disulfide,
Examples include dibenzyl disulfide, diphenyl disulfide, dibenzoyl disulfide, and diacetyl disulfide. Examples of peroxides include hydrogen peroxide, di[-butyl peroxide, benzoyl peroxide, and methyl ethyl ketone peroxy F. Furthermore, redox compounds consist of a combination of a peroxide and a reducing agent, and include ferrous ions and hydrogen peroxide - ferrous ions and persulfate ions, ferric ions and peroxides, etc. .

Examples of azo and diazo compounds include .alpha..alpha.'-azobisisobutyronitrile, 2-azobis-2-methylbutyronitrile, 1-azobis-cyclohexanecarbonitrile, and diazonium salts of P-aminodiphenylamine. Halogen compounds include chloromethylnaphthyl chloride, phenacyl chloride, chloroacetone, β
-Naphthalenesulfonyl chloride, xylenesulfonyl chloride, etc. can be mentioned. In addition, photoreducible pigments include rose bengal, erythrosin, eosin,
These include acriflavin, riboflavin, and thionin.

The photopolymerization initiators mentioned above may be used alone or in combination of two or more. The amount used is usually 0.1 to 20 parts by weight per 100 parts by weight of the ethylenically unsaturated polymerizable compound.
It is desirable that the amount be within the range of parts by weight.

Thermal polymerization inhibitors include paramethoxyphenol, hydroquinone, alkyl group- or aryl group-substituted hydroquinone, t-butylcatechol, pyrogallol-cupric chloride-monofetthiazine, floranil, naphthylamine, β
-Naphthol, 26-di-L-butyl-P-cresol, pyridine, nitrobenzene, dinitrobenzene, P-
Examples include toluidine-methylene blue and organic acid copper such as copper acetate. These thermal polymerization inhibitors are generally used in an amount of 0.001 to 5 parts by weight per 100 parts by weight of the ethylenically unsaturated polymerizable compound.

Also, fillers include calcium carbonate, clay, powdered silica, talc, and the like. The amount added is preferably less than 50% by weight of the entire composition.

The pressure-sensitive adhesive composition thus constituted is usually dissolved in a solvent, cast on a support, and then dried to form a pressure-sensitive adhesive with a thickness of about 5 to 1 m, preferably 10 to 5 oI, about 1 m thick. form a layer. If the thickness is less than 51 tm, the dust removal effect will be low, which is not preferable, and if it exceeds 100 μm, it will tend to leave residue, which is not preferable.

As the support, a plastic film or paper such as polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, etc. is used. Note that the support may be subjected to a commonly used surface treatment in order to increase the adhesive strength between the support of the adhesive tape and the adhesive layer.

Examples of this surface treatment include coating of an undercoat layer - corona discharge treatment, flaming treatment, ultraviolet irradiation treatment - high frequency irradiation treatment, glow discharge irradiation treatment, active plasma irradiation treatment, laser beam irradiation treatment, etc.

In the method of the present invention, the adhesive tape obtained as described above is brought into close contact with the surface of a printed wiring board that has been chemically or mechanically surfaced, and then peeled off to remove dust from the surface of the board, and then photo After a resist is laminated and adhered to the substrate, a printed wiring board is manufactured according to a conventionally known method.

In order to adhere the above-mentioned adhesive tape to the substrate surface, in addition to normal bonding, it is necessary to move a roll of adhesive tape wrapped around the substrate so that the adhesive layer is on the outside,
Alternatively, this roll-like material and a silicone roll may be opposed to each other, and the substrate may be moved between them. After this close contact, the tape is peeled off and a photoresist is laminated on the surface of the substrate from which dust has been removed. From the viewpoint of workability, it is preferable to use a dry film resist. When using this dry film resist, it is pasted on the surface of one substrate and then heated and pressed using a laminating roll or the like to completely adhere to it to form a laminate.

Actinic light is irradiated through the original image from the photoresist side of this laminate to form a pattern. The active light used here is 200 to 7QQnm, preferably 350 to 7QQnm.
There are ultraviolet rays and visible rays of 45 Qnm, and suitable light sources include low-pressure, high-pressure-ultra-high pressure mercury lamps, xenon lamps, carbon arc lamps, halogen lamps, germicidal lamps, and the like.

In addition, electron beams, X-rays, laser beams, etc. are also effective.

After this light irradiation, an image is formed by a known development method such as a peel development method or a solution development method, but it is preferable to employ the peel development method in terms of working efficiency and working environment. After forming an image in this way, the exposed copper foil is removed by etching, and then the resist image is removed with a solvent such as methylene chloride, washed with water, and dried to form a predetermined circuit pattern. A printed wiring board without defects such as circuit breakage can be obtained.

Hereinafter, examples of this invention will be described. In the following, parts indicate parts by weight.

Example 1 Chlorinated polyethylene (Super Q 7 CPE-9Q7HA manufactured by Yamaba Kokusaku Pulp ■) 7 Q part polymethyl methacrylate (Mitsubishi Rayon (Dianal BR manufactured by Kiki)
-75) 20 parts linear saturated polyester (Toyobo Co., Ltd. (Kiki-made Byron #200) 10 parts acrylic unsaturated polymerizable compound "'" (Toagosei Kagaku Kogyo ■ Aroex M-6], 00) 70 parts Pen Erythritol Triacrylate 50 parts Para-methoxyphenol 0.15 parts Methyl ethyl ketone/toluene (]/1: weight ratio) 400 parts A pressure-sensitive adhesive composition in which each of the above components was uniformly dissolved or dispersed was prepared using a 25/1 m thick polyethylene telescope plate (Tokyo). ■
The adhesive tape was applied to a dry thickness of 30 μm on Lumirror #25) manufactured by Co., Ltd., and heated at 100°C for 5 minutes to obtain an adhesive tape. The adhesive strength of this adhesive tape is 160y/25 scale (30
'C).

Next, the adhesive tape was flattened (dried copper foil) and brought into close contact with the copper foil surface of the lath epoxy laminate board, and then rolled and pressed at -25°C. While peeling off the adhesive tape on this board, Compounds with at least one addition-polymerizable unsaturated bond such as ester-alkyl methacrylate esters, film-forming polymeric substances such as chlorinated polyolefins, vinyl chloride-vinyl acetate copolymers, carbonyl compounds-peroxides, etc. A peelable and developable dry film resist (product name: NEODROCK-■ manufactured by Nitto Kokei Kogyo ■) consisting of a photopolymerization initiator, thermal polymerization inhibitor, dye, etc. was adhered to the copper foil surface of this substrate, and rolled at 25°C. In this state, pattern exposure was carried out for 20 seconds from a distance of 60 (1) using a 3 KW ultra-high pressure mercury lamp from the transparent thin film side of the resist through the original image in which the circuit pattern part was transparent.

Then, by peeling off the transparent thin film of the resist and the uncured portion of the photopolymerizable composition layer at a peeling angle of 90° at 35°C and a speed of −1.0 m/min, the original image is applied onto the copper foil. A hardened image was formed.

After this image formation, the exposed copper foil was etched away by etching using a ferric chloride aqueous solution at about 40° Baume. Thereafter, the cured resist image was removed with methylene chloride, washed with water, and dried to obtain a printed wiring board having a predetermined pattern.

This printed wiring board was used as a multipurpose projector made by Mitoyo Seisakusho, PJ-
When inspected with 311 magnification of 100 times, out of the 10 sheets, there were no circuit breakage defects caused by foreign matter remaining on the board, unremoved adhesive layer of the adhesive tape, or contamination.

Example 2 The same adhesive tape as in Example 1 was brought into close contact with the copper foil surface of a prepared and dried copper foil-glass epoxy laminate board, and roll pressure was applied at 25°C. Then, while peeling off the adhesive tape on the substrate, a solution-developable type containing an acrylic ester polymer, an acrylic ester polymerizable unsaturated compound, a chelating agent to a thermal polymerization termination inhibitor, a dye, a photopolymerization initiator, etc. A dry film resist (product name Riston-1220 manufactured by Teyupon) was adhered to the copper foil surface of this board, and 11
Lamination was carried out at 0°C by applying roll pressure. In this state, pass through the original image in which the circuit pattern part is transparent, and use a 3Kw ultra-high pressure mercury lamp to remove 60cm from the transparent thin film side of the resist.
The pattern was exposed for 17 seconds from a distance of .

Thereafter, the transparent film of the resist was peeled off, and the uncured portion of the resist was removed by immersing the substrate in 1°1'1'J chloroethane for 2 minutes at 20°C, and the cured image was developed. Formed.

Thereafter, printed wiring boards were prepared and inspected in the same manner as in Example 1, and as in Example 1, there were no circuit breakage defects among the 10 boards.

Example 3 Chlorinated polyethylene (Superclone CPE-907LTA manufactured by Sanyo Kokusaku Pulp■) 100 parts Oligoester acrylate (Aloex M-8060 manufactured by Toagosei Kagaku Kogyo 0(1)) 70ffi diethylene glycol diacrylate 70 parts Aerosil 10 parts Paramethoxyphenol 0.1 parts Toluene 400 parts The adhesive composition in which each of the above components was uniformly dissolved or dispersed was mixed with a 0.1 am thick polyvinyl chloride film (100 parts of Nippon Zeon (Kiki Seisaku Shichion 151) and It was applied onto a cast film (containing 35 parts of dioctyl phthalate) to a dry thickness of 25 μm and heated at 80°C for 10 minutes to obtain an adhesive tape.The adhesive strength of this adhesive tape was 10
It was 0 fJ/25 am width ((30°C)).

Thereafter, printed wiring boards were produced and inspected in the same manner as in Example 1, and as in Example 1, no circuit breakage defects were found among the 10 boards.

Example 4 Chlorinated rubber (Super Chron CR-5 manufactured by Nanyo Kokusaku Pulp ■)
) 65 parts Copolymer of methyl methacrylate (70 parts) and phthyl acrylate (30 parts) 20 parts linear saturated polyester (Nispel 1510 manufactured by Hitachi Chemical Co., Ltd.) 15 parts Acrylic unsaturated polymerizable compound (Toa Co., Ltd.) Aroex M6100 (manufactured by Synthetic Kagaku Kogyo ■) 70 parts Pentaerythritol triacrylate 60 parts Rose methoxyphenol
O, 15 parts Methyl ethyl ketone/toluene 400 parts (1/1:
Weight ratio) An adhesive composition in which each of the above components was uniformly dissolved or dispersed was applied onto a 25 ttm thick polyethylene terephthalate (Lumirror #25 manufactured by Toshi ■) so that the dry thickness was 407 zm, and the adhesive composition was heated at 100°. The adhesive tape was obtained by heating at C for 5 minutes. Is the adhesive strength of this adhesive tape 250F? /
25 wn width (30°C).

Next, printed wiring boards were prepared and inspected using this adhesive tape in the same manner as in Example 1, and as in Example 1, no circuit breakage defects were observed among the 10 boards.

Comparative Example A printed wiring board was prepared in the same manner as in Example 1 using a commercially available pressure-sensitive adhesive tape (manufactured by Nitto Electric Industries @, No. 712 Kraft Tape) with an adhesive layer or natural rubber. During the peeling process, the peeling force of this tape was large and the workability was poor.

In addition, when inspected in the same manner as in Example 1 - this wiring board 10
Four of the sheets had circuit disconnections due to contamination from the tape used for dust removal or adhesive residue.

Patent applicant: Nitto Electric Industry Co., Ltd.

Claims (3)

[Claims] (1) In the production of printed wiring boards, dust removal from the surface of the printed wiring board before photoresist is laminated is performed so that the adhesive layer contains a) chlorinated polyolefin and/or chlorinated rubber, b) acrylic acid alkyl ester or methacrylic acid. A linear saturated polyester consisting of an alkyl ester polymer and C) terephthalic acid, ethylene glycol, and a dibasic acid or dihydric alcohol other than these and having an average molecular weight of about 30,000 or less and having a carboxyl group or a hydroxyl group at the molecular end. The adhesive layer contains at least one film-forming polymeric substance selected from among these and an ethylenically unsaturated polymerizable compound as essential components, and the adhesive layer has a thickness of 5 to 100 μm and an adhesive strength of 50 to 1,500 y. / 25 tnm width (30° C.) A method of manufacturing a printed wiring board, characterized in that the adhesive tape is adhered to the surface of the substrate and then peeled off. (2) The method for manufacturing a printed wiring board according to claim (1), wherein a dry film resist is used as the photoresist. (3) The method for manufacturing a printed wiring board according to claim (2), which uses a photoresist for peeling and development.